/** 脚本设定卡的选项体系:表现形式 × 视频结构 × 时长(二期第2段)。
 *
 * 这里的枚举、禁用组合、时长区间必须跟后端 apps/ai/script_agent.py 的常量保持一致 ——
 * 后端会 coerce 兜底,但前端先挡住能避免用户选了一个又被悄悄改掉。
 */

export type PresentationFormat = "oral" | "drama" | "vlog";
export type VideoStructure = "pain" | "contrast" | "review" | "scene" | "promo" | "knowledge";

export const PRESENTATION_FORMATS: Record<PresentationFormat, string> = {
  oral: "口播",
  drama: "短剧",
  vlog: "Vlog",
};

export const VIDEO_STRUCTURES: Record<VideoStructure, string> = {
  pain: "痛点解决",
  contrast: "前后对比",
  review: "测评验证",
  scene: "场景种草",
  promo: "促销抢购",
  knowledge: "知识分享",
};

export const PRESENTATION_KEYS = Object.keys(PRESENTATION_FORMATS) as PresentationFormat[];
export const STRUCTURE_KEYS = Object.keys(VIDEO_STRUCTURES) as VideoStructure[];

const FORMAT_KEY_BY_LABEL: Record<string, PresentationFormat> = Object.fromEntries(
  (Object.entries(PRESENTATION_FORMATS) as Array<[PresentationFormat, string]>).map(([key, label]) => [label, key])
);
const STRUCTURE_KEY_BY_LABEL: Record<string, VideoStructure> = Object.fromEntries(
  (Object.entries(VIDEO_STRUCTURES) as Array<[VideoStructure, string]>).map(([key, label]) => [label, key])
);

/** 脚本落库存的是中文标签(「短剧」),设定卡下拉用的是 key(drama)。两边都认。 */
export function coercePresentationFormat(value: unknown, fallback: PresentationFormat = "oral"): PresentationFormat {
  if (typeof value !== "string" || !value) return fallback;
  if (value in PRESENTATION_FORMATS) return value as PresentationFormat;
  return FORMAT_KEY_BY_LABEL[value] || fallback;
}

export function coerceVideoStructure(value: unknown, fallback: VideoStructure = "pain"): VideoStructure {
  if (typeof value !== "string" || !value) return fallback;
  if (value in VIDEO_STRUCTURES) return value as VideoStructure;
  return STRUCTURE_KEY_BY_LABEL[value] || fallback;
}

/** 一句话说清每个选项是什么,挂在下拉旁边当说明,别让用户猜。 */
export const PRESENTATION_HINT: Record<PresentationFormat, string> = {
  oral: "一个人对镜头说,信息密度最高、最省制作",
  drama: "有角色有冲突的微型剧,完播率最高",
  vlog: "第一人称生活记录,广告感最低",
};

export const STRUCTURE_HINT: Record<VideoStructure, string> = {
  pain: "先戳痛点再给解法,适用面最广",
  contrast: "用前后差距说话,视觉冲击最强",
  review: "当场举证验证,适合高客单价",
  scene: "把商品放进向往的场景里种草",
  promo: "优惠机制清楚时,直接讲怎么买最划算",
  knowledge: "先教用户怎么判断,再自然带出商品",
};

/** 唯一禁用组合:短剧 × 测评验证 —— 演出来的实测没有可信度。 */
const FORBIDDEN: ReadonlyArray<[PresentationFormat, VideoStructure]> = [["drama", "review"]];

export function isForbidden(format: PresentationFormat, structure: VideoStructure): boolean {
  return FORBIDDEN.some(([f, s]) => f === format && s === structure);
}

/** 1.8 组合联动:选定表现形式后,视频结构只剩这些可选。 */
export function allowedStructures(format: PresentationFormat): VideoStructure[] {
  return STRUCTURE_KEYS.filter((key) => !isForbidden(format, key));
}

// ── 时长:总时长 15/30/45/60;主流程每镜固定 15 秒 ──
export const SEGMENT_DURATION_MIN = 4;
export const SEGMENT_DURATION_MAX = 15;
export const TOTAL_DURATION_MIN = 15;
export const TOTAL_DURATION_MAX = 60;
export const TOTAL_DURATION_STEP = 15;
export const DURATION_OPTIONS: number[] = Array.from(
  { length: (TOTAL_DURATION_MAX - TOTAL_DURATION_MIN) / TOTAL_DURATION_STEP + 1 },
  (_, i) => TOTAL_DURATION_MIN + i * TOTAL_DURATION_STEP
);

/** 表现形式推荐的默认总时长:口播短平快 / 短剧要装下三幕 / Vlog 要铺氛围。 */
const FORMAT_DEFAULT_DURATION: Record<PresentationFormat, number> = { oral: 30, drama: 45, vlog: 30 };
/** 各结构能压到的最短总时长 —— 低于它证据或氛围就不成立了。须落在 15 秒步进上。 */
const STRUCTURE_MIN_DURATION: Record<VideoStructure, number> = { pain: 15, contrast: 15, review: 30, scene: 30, promo: 15, knowledge: 30 };

export function recommendDuration(format: PresentationFormat, structure: VideoStructure): number {
  return Math.max(FORMAT_DEFAULT_DURATION[format], STRUCTURE_MIN_DURATION[structure]);
}

export function clampDuration(seconds: number): number {
  if (!Number.isFinite(seconds)) return FORMAT_DEFAULT_DURATION.oral;
  const stepped = Math.round(seconds / TOTAL_DURATION_STEP) * TOTAL_DURATION_STEP;
  return Math.min(TOTAL_DURATION_MAX, Math.max(TOTAL_DURATION_MIN, stepped));
}

/** 时长低于该结构的最短可用值时给一句提醒(不拦,只提示)。 */
export function durationWarning(structure: VideoStructure, seconds: number): string {
  const min = STRUCTURE_MIN_DURATION[structure];
  if (seconds >= min) return "";
  return `${VIDEO_STRUCTURES[structure]}低于 ${min} 秒会压不住,建议调长`;
}

// ── 2.3 按商品分类推荐默认组合 ──

type Combo = { format: PresentationFormat; structure: VideoStructure; persona: string };

/** 与商品库品类一一对应。改这里时同步 backend script_agent.recommend_script_setup。 */
const CATEGORY_COMBOS: Record<string, Combo> = {
  美妆个护: { format: "oral", structure: "contrast", persona: "bestie" },
  食品饮料: { format: "oral", structure: "scene", persona: "bestie" },
  服饰鞋包: { format: "oral", structure: "scene", persona: "urban" },
  家居日用: { format: "oral", structure: "pain", persona: "mom" },
  数码家电: { format: "oral", structure: "review", persona: "reviewer" },
  母婴玩具: { format: "oral", structure: "pain", persona: "mom" },
  运动健康: { format: "oral", structure: "scene", persona: "urban" },
  珠宝配饰: { format: "oral", structure: "scene", persona: "ceo" },
  汽车用品: { format: "oral", structure: "review", persona: "reviewer" },
  宠物用品: { format: "oral", structure: "pain", persona: "mom" },
  图书文教: { format: "oral", structure: "knowledge", persona: "urban" },
  五金农资: { format: "oral", structure: "review", persona: "reviewer" },
  其他商品: { format: "oral", structure: "pain", persona: "urban" },
};

/** 旧品类名 / 标题关键词兜底。命中第一条即用。 */
const CATEGORY_RULES: ReadonlyArray<{ keywords: string[]; combo: Combo }> = [
  { keywords: ["美妆", "护肤", "彩妆", "面膜", "精华", "洗护", "个护"], combo: CATEGORY_COMBOS["美妆个护"] },
  { keywords: ["保健", "营养", "膳食", "益生菌", "维生素"], combo: { format: "oral", structure: "review", persona: "reviewer" } },
  { keywords: ["数码", "3c", "电子", "电器", "手机", "耳机", "相机", "工具", "家电"], combo: CATEGORY_COMBOS["数码家电"] },
  { keywords: ["食品", "零食", "饮料", "咖啡", "茶", "生鲜", "酒"], combo: CATEGORY_COMBOS["食品饮料"] },
  { keywords: ["服饰", "女装", "男装", "服装", "鞋", "包", "配饰", "内衣"], combo: CATEGORY_COMBOS["服饰鞋包"] },
  { keywords: ["家居", "家纺", "收纳", "厨具", "清洁", "日用"], combo: CATEGORY_COMBOS["家居日用"] },
  { keywords: ["母婴", "宝宝", "儿童", "玩具"], combo: CATEGORY_COMBOS["母婴玩具"] },
  { keywords: ["宠物"], combo: CATEGORY_COMBOS["宠物用品"] },
  { keywords: ["户外", "露营", "运动", "健身"], combo: CATEGORY_COMBOS["运动健康"] },
];

const FALLBACK_COMBO: Combo = { format: "oral", structure: "pain", persona: "urban" };

/** 按商品品类推荐「表现形式 × 视频结构 × 人物 × 时长」。用户随时可改。 */
export function recommendSetup(input: { category?: string; title?: string }): Combo & {
  duration: number;
  reason: string;
} {
  const category = (input.category || "").trim();
  const haystack = [category, input.title]
    .filter(Boolean)
    .join(" ")
    .toLowerCase();

  let combo = FALLBACK_COMBO;
  let reason = "商品信息不足,先给一组最通用的";
  if (category && CATEGORY_COMBOS[category]) {
    combo = CATEGORY_COMBOS[category];
    reason = `按「${category}」品类推荐`;
  } else {
    for (const rule of CATEGORY_RULES) {
      const hit = rule.keywords.find((word) => haystack.includes(word.toLowerCase()));
      if (hit) {
        combo = rule.combo;
        reason = `按「${hit}」品类推荐`;
        break;
      }
    }
  }
  // 自动推荐只给口播；Vlog / 短剧留给用户自己选。
  const format: PresentationFormat = "oral";
  const structure = isForbidden(format, combo.structure)
    ? allowedStructures(format)[0]
    : combo.structure;
  return {
    format,
    structure,
    persona: combo.persona,
    duration: recommendDuration(format, structure),
    reason,
  };
}